Re: [PATCH vv2 1/1] gdb: fix assert after register write failure

[Tom Tromey <tom@tromey.com>]

>>>>> "Stephan" == Stephan Rohr <stephan.rohr@intel.com> writes:

Stephan> From: Eduard Sargsyan <eduard.sargsyan@intel.com>
Stephan> GDB tries to invalidate register cache if write to register fails.  In case
Stephan> when write was requested to be done for a remote inferior and connection with
Stephan> remote is dead (so write request will fail) GDB cleans register caches and as
Stephan> result setting register status fails with segmentation fault, because internal
Stephan> pointers are not valid anymore and the unique_ptr with register status is
Stephan> null.

Stephan> This change adds check if register status cache is still valid before trying to
Stephan> modify (set status to UNKNOWN).

I don't mind this patch but I do wonder about it a little.

I couldn't find where m_register_status is reset.  How does this part
work?  Like, what set this to 'nullptr'?

And I wonder about the contract of this object.  I understand wanting
this particular spot to do this check.  But there are many other things
that access m_register_status.  Do those need checks, in theory, to
preserve some invariant?  Or just invalidation?

thanks,
Tom